1. Field of the Invention
The present invention relates to an image recording apparatus utilizing an electrophotographic process such as a laser beam printer or a copier, and more particularly to such image recording apparatus capable of adequately controlling the image recording conditions thereby constantly providing clear images.
2. Description of the Prior Art
As an example of an image recording apparatus utilizing an electrophotographic process there is already known the so-called laser beam printer.
In such printer a photosensitive drum composed of a photoconductive material is first uniformly charged and then exposed to a laser beam to form an electrostatic latent image. Said image is rendered visible with toner, and the obtained visible image is transferred onto a plain paper sheet (transfer sheet) and fixed thereon to obtain a hard copy. In such printer the intensity of the laser beam has to be maintained at an appropriate level in order to obtain a latent image of an adequate potential contrast. In case the intensity of the laser beam is below an adequate level, the potential contrast of the latent image becomes deficient for satisfactory image development, so that the obtained image will have an insufficient density. On the other hand, in case the intensity of the laser beam is excessive, image lines become thicker though the image density is sufficient, so that a clear image cannot be obtained. For this reason, even if the printing operation is conducted with such an intensity of laser beam as to obtain an optimum potential contrast, clear images cannot often be obtained because of thick image lines.